It is well known art to photographically project or to contact print a series of font characters from a negative film font upon a piece of sensitized paper until a complete message has been exposed onto a photographic paper emulsion. However, to produce a full magazine-size page of display typography on a full sheet of photo paper with some of the ascending and descending parts of the characters interlocking or overlapping vertically from line to line, existing daylight functioning machines are unsatisfactory for many reasons. In existing machines the completed, overlapped display typography on a full sheet of photographic paper can be accomplished only by a commercial artist who must perform tediuos, expensive, time-consuming labor which requires cutting apart, mechanical paste-up, manual artwork then photostating the composition, to accomplish the desired final result.
In the present state of the art, an operator who is called away from an incompleted composition could lose continuity of the copy and misspell words on a blind operating device, could create overdevelopment, fog and streaks on a constantly wet photo paper machine, and/or have the previous character images disappear on a phosphorescent character image retaining machine.
In the present state of the art, daylight operating photo lettering and display typography composing devices with visual spacing facilities for display composing, are slow in font character selection. Blind operating machines have faster font character selection. However, the resulting display composition from all the existing blind machines have poor spacing and require laborious art work to complete vertically overlapped line-over-line display typography.
The devices that are slow in font character selection use either a negative film front strip on two reels which requires hand winding back and forth past the light path area to visually select the desired character, or a rigid framed negative film font that requires transverse and longitudinal movement past the light path area for visual selection of the desired character.
One form of a present device provides visual composition control, but functions only in a darkroom and requires wiping on of a photographic developer to the sensitized material. The result is a product with variation in character density caused by uncontrollable development time, with greater development time for the initially composed font characters that remain on the developer-wetted paper for a longer time, and the possibility of background fog and streaking from extraneous light. Precise spacing control is difficult under darkroom lighting conditions with this machine.
Another form of a photo lettering and display typography device functions in daylight, employing an excited phosphor character image of the previously imprinted character as a spacing guide. However, the phosphorescent image is of short duration and, as a result, line-over-line composition which requires long duration retention of the excited font character images is impossible.
Another known photo lettering and display typography device is limited to the use of a two-inch wide strip of sensitized paper which is immersed under a layer of developer solution for the entire composition period, Friedel, U.S. Pat. No. 3,115,815, FIG. 6, No. 16. Overdevelopment of the initial characters results from long duration, small character composition such as line-over-line copy within the limited confines ot the 2-inch paper strip.
Another presently known photo lettering and display typography device employs a two-paper method utilizing a photographic developer-wetted paper for visualization and a dry-image paper subsequent processing into the finished copy. This device operates only in a darkroom and is slow because the operation requires additional motions for the first exposure of the font character on the wetted paper, removal of the exposed wet paper from the image path, a second exposure on dry paper, return of the wet paper and so on with subsequent processing of the dry paper after the entire composition is completed.
Another photo lettering and display typography device of the present art has rapid character selection, functions in daylight, but is operated totally blind without visual operator spacing control.
The poor, fixed, non-kernable spacing of the characters subsequent to imprinting on all blind operating devices, requires the cutting apart of the finished composition and repositioning, cementing and retouching of the characters to achieve overlap and good spacing. Since no visual indications of the prior imprinted characters are visible to the operator, spelling errors resulting from interruption of forgetfulness also occur.